Sunday’s collision in Flagstaff, Ariz., of two air-ambulance helicopters, one of which was operated by a Denver-area company, has national air-safety officials looking again for ways to improve safety in the air medical industry.

It was the ninth accident this year involving emergency medical aircraft, bringing the number of deaths to 16, National Transportation Safety Board officials said Monday.

The accident Sunday involved two helicopters that were arriving with patients at the Flagstaff Medical Center. Six people were killed and one injured.

“This has been a serious issue,” NTSB chairman Mark Rosenker said. “We’re going to work very, very hard to make sure we understand exactly what happened here, determine the probable cause and make recommendations to prevent it from happening again.”

One of the helicopters in the Flagstaff collision was coming from the South Rim of the Grand Canyon, about 70 air miles from Flagstaff. The drive on well-paved roads takes about 90 minutes.

The other chopper, which is owned by the Flagstaff hospital, was bringing a patient from Winslow, about 50 miles east of Flagstaff on Interstate 40.

Air Methods Corp., of Arapahoe County, the nation’s largest air-ambulance company, provided the pilot and maintenance for the Flagstaff hospital’s helicopter, said Paul Tate, Air Methods’ chief operating officer.

Tate said that the weather was good and that the two pilots were operating under visual flight rules.

He said the helicopter flown by the Air Methods pilot had stopped first at the airport in Flagstaff before proceeding to the medical center.

NTSB spokesman Keith Holloway said the stop was made to let a flight nurse get off the aircraft.

Rosenker said the crew member was dropped off so the helicopter could meet weight requirements for landing at the hospital.

NTSB retrieved surveillance video from the hospital that may show the collision, but it has been sent back to the agency’s Washington, D.C., headquarters to be “enhanced” so it can be of use, Holloway said.

Air Methods, based near Centennial Airport, operates a fleet of more than 340 helicopters and fixed-wing aircraft in 42 states, according to company data.

Tate, a former top Frontier Airlines executive, joined Air Methods in March.

“My primary mission at Air Methods is to continue to find ways to improve our margin of safety,” he said.

The company has about 40 percent of the air-ambulance market, Tate said.

He said the Air Methods pilot on the Flagstaff hospital helicopter was highly experienced, with 5,200 total flight hours including 4,500 in rotor craft.

In May, an Air Methods-operated medical helicopter crashed when it collided with trees near La Crosse, Wis. All three on board — the pilot, a physician and a flight nurse — were killed.

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